High voltage testing system



Aug. 16', 1932. R, TA BER 1,872,362

HIGH VOLTAGE TESTING SYSTEM Filed March 6. 1829 INVENTOR Ragnar Tanberg.

WW ATTORNEY Patented Aug lfi, 1 932 UNITED STATES PATENT OFFICE BAGNAR TANB EBG, PITTSBURGH, PENNSYLVANIA, ASSIGNOB T0 WESTINGHOUSE ELECTRIC &- MANUFACTURING COMPANY, A CORPORATION 01' PENNSYLVANIA HIGH VOLTAGE TESTING SYSTEM Application filed larch 8,

My invention relates to high-voltage testing systems and more particularly to methods of and means for applying hi h voltages to test circuits at accurately pre etermined instants of time.

Heretofore, mechanical switching equip-- ments have been used for this purpose but they have an inherent inaccuracy by virtue of the fact that the striking distance between the moving contacts varies, as well as the conditions surrounding them, such as, the degree of ionization of the air and the like which precludes consistent accuracy in a plying high voltages to test circuits at pre etermined instants of time.

The object of my invention is to provide a method of-and means for the application of a high voltage to a test circuit at an accurately predetermined instant of time, with a consistent accuracy in the order of microseconds that is impossible to accomplish by means of mechanical switching equipment.

My invention may be more readily understood if the accompanying drawing is referred to in connection with the following description.

The single figure of the drawing is a schematic diagram of a system constructed in accordance with my invention.

A vacuum tube 1, having the usual heated filament 2, grid 3 and plate 4 housed in an evacuated tube, has its filament 2 and plate 4 connected, by conductors 6 and 7, respectively, to spark-gap electrodes 8 and 9. The grid 3 of the tube 1 is connected, by a conductor 10, to a switch 11 which is provided with a contact 12 and a contact 13. The con 'tacts 12 and 13 are connected, respectivel ner, by any direct-current source (not shown). O

The spark-gapelectrodes 8 and9 are in series w1th another spark-gap electrode that ma be provided with a condenser 21 in para el-circuit relation with it and the 1929, Serial No. 34:4,851.

electrode 9. The spark-gap electrodes 8 and 20 are connected, by conductors 22 and 23, to condensers 24 and a test circuit, in the present case, a resistor 25. The condensers 24 are charged, by'any suitable means, to

a high value of voltage, say to the magnitude of 15,000 volts or more. A conductor 26,

connected between the condensers 24 and the resistor 25, completes a series-circuit relation of the condensers 24, the spark-gaps 89 and 9-20 and the resistor 25. The latter is grounded at 27 for safety.

The distances between the spark-gap electrodes 8, 9 and 20 are so set that they just do not spark over at the voltage distribution produced by the capacity, and leakage of thecondenser 21 and the capacity and conductance between filament 2 and plate 4, with the filament heated and the switch 11 contest resistor 25.

In this manner, a high voltage is applied to the test circuit at an accurately predetermined instant, with a consistent accuracy in the order of microseconds, which high degree of accuracy, as pointed out above, has heretofore been impossible to obtain with mechanical switching arrangements. Y

In some cases, where every high voltage is to be applied to the test circuit 25, it may be necessary to use a condenser 28 (shown in dotted lines) across the electrodes 8 and 9, to which the filament 2 and the plate "4 are connected. This limits the potential across the elements of the tube to values which may be safely applied. to 'commercialtubes. The

ordinary commercial tubes will stand about 15,000 volts although some are built to stand 7 50,000 volts, but the expense of these make it desirable to use the lower-voltage tubes.

Also the condenser 21 may bemade of a.

' very small capacity or omitted entirely, when very high vo tages. are used in the test circuit and the voltage across the tube is to be limited, the voltageacross the spark-gap electrodes varying inversely as the capacity of the condensers.

Various changes may be made in my invention without departing from the spirit thereof, as set forth in the following claims.

series-circuit relation with sai gaps, a thermionic tube having its filament I claim as my invention: 1. The combination with a source of high voltage, of means for impressing said voltage on said test circuit at an accurately predetermined instant of time,

said means includingaspark gap, and a thermionic tube for changing the voltage across. said spark gap to cause itto break down.

a test circuit andcluding a thermionic tube across one of said gaps 'for changing the voltage across said for causing said gap to break down.

testimony whereof, I have hereunto subscribed my name this 23rd day of February, 1929.

' RAGNAR- TANBERG.

2. 'In combination, a source of high voltage,

a test circuit, a plurality of s ark gaps in source and said circuit, a condenser across one of said gaps, and means across another of said gaps for changing the Volta e across said gaps I and causing said con enser to discharge across its gap, thereby causing said other gap to break down.

3. In combination, a plurality of spark and plate connected across one of said gaps,

and means for changing the grid bias of said tube, thereby changing the voltage distribution of said spark gap.

4. In combination, a plurality of sparkvoltage source and a plurality of separated spark-gap electrodes in circuit, relation therewith, a condenser across two of said elec- "trodes, a circuit including the plate and filament of a thermionic tube across two of said electrodes, and means for changing the grid bias of said tube irom negative to positive,

thereby chargin said first named condenser to a value where y it discharges across said first named electrodes, followed by the immegiate discharge across said spark-gap electro es.

6. The combination a Volta e source and a test circuit, of means for app ying the voltage of said source to said test circuit including a'plurality of spark gaps and a thermomc tube for changing the voltage of said The combination with a high-voltage circuit including a plurality of, spark gaps,

condensers across said gaps, and means m- 

